21" 1700 cu. in. Tactical Sling Shoulder Hiking Backpack BB002 Perfect for outdoor use! Tactical Messenger Body Sling backpack Capacity: 1700 cu. in. Size: 21(Height) x 13(Width) x 6(Depth) Triangular shaped, Detachable Padded shoulder strap with Velcro and Audio pass-through hole in front pocket